ON THEDISEASESOFLiteraryandSedentary Persons.

When I consider with myself how many and how great men have formerly ascended this chair, with how general an applause they apply’d to the education of youth, and how every branch of erudition has been cultivated to such advantage by the present set of teachers, into whose learned order I am this dayadmitted by the great favour and indulgence of our senate; whilst I at the same time reflect how much this new situation differs from my former manner of living, in which as I had willingly pass’d a considerable part of my life, I had determin’d to continue to my old age; when I reflect upon all these circumstances, a tremor seizes my limbs, and my voice falters. But because from the very foundation of this respectable academy, custom, which governs all things, and your expectation requires it of me, embolden’d by your kindness, I will make trial of my abilities.

Being a new member, and ascending a new chair, I propos’d to speak of the connexion between physic and other academical studies, and it wasmy design to explain what it borrows from them, and what it contributes to them in its turn.

It would be a pleasure to me, reverend pastors of the church, and illustrious professors of divinity, to declare aloud how much physick is indebted to religion; I would gladly vindicate the principles of physicians from the imputations of ancient calumny, and prove that religion is strongly supported by a science, which, being totally conversant in the contemplation of an admirable creature, demonstrates from the wonderful mechanism of a man in health, and the surprising cures of the sick, the existence and great wisdom of the Supreme Artificer, and that even to the most obstinate. Do men forget the Deity?Physicians stand forth, and theology is entirely reviv’d; for who have spoken more truth, or in a sublimer stile concerning God, than they? There would be no end, were I to cite them all; but I must not pass over in silenceHippocrates, the first who ever asserted that fate produc’d nothing, but that all those events, which we call fortuitous, are regulated by the will of God: the next to him isGalen, who diffusively proves, that the existence of God is demonstrated by the position of the thumb alone; and calls his treatise concerning the use of the parts, a monument to the glory of the Deity: to him must be addedPolychrestus, to whom the illustrious sir-name ofLover of Godwas given, on account of his great piety:Boyle, who wrote excellent works himself,and founded an admirable institution for the promotion of religion, which he nobly endow’d; his friendSydenham; the immortalLock;Hoffman, who carried his piety so far, that he was not entirely free from superstition; the admirableTralles; and my dear and worthy friendHaller, who in an excellent treatise has asserted the utility of religion in a manly stile, as usual, and exerts himself to the utmost to promote its cause.

Physicians indeed laugh at the idle tales of old women, at the extravagancies of the vulgar, and thereby incur the censure of weak and superstitious people; they deride the inventions of imagination; and whilst every divine lays down his own opinion as the rule of truth, physicians make a jest ofthe phantoms which these set up for religion, and refuse to embrace a cloud for a Juno: thence all these clamours, these accusations, these reproaches, and these calumnies. But if some of our society have in fact been led astray by error, which I am sorry to say cannot be denied, the severe censure of their colleagues has soon convinced the public how much they disapprov’d of their principles.

It would be a pleasure to me, most learned professor of morality, whom to address by the tender name of father-in-law is my greatest happiness; it would be a pleasure to me, I say, to treat to the best of my abilities of the connexion between the knowledge of morals and of health; how near the relation is between them,how exact the concatenation in every respect. This is certainly both an agreeable and useful undertaking: nor is it altogether new; forHippocrateshas in his whole treatise concerning diet, done his utmost to prove that souls are the same in all men, and that the various degrees of wisdom and folly proceed from the different temperament of their bodies; andGalen, who has admirably demonstrated the power of the body over the mind and the motions of the will, desired the teachers of philosophy, sixteen ages ago, to send all persons of bad morals to him to be cur’d[1].

Should I be ever so full, most learned professor of jurisprudence, I could not entirely display the connexion between us; for whether alegislator regulates a commonwealth, or whether a judge upon the bench weighs questions of civil law, or criminal and ecclesiastical causes, in the ballance of Themis, there occur cases, and those not a few, in which he cannot do without the assistance of our art.

It would be necessary to lay open the greatest part of natural knowledge, most profound professor of philosophy, were I to treat of all that it has in common with physick; for you well know that both the cure of diseases, and the contemplation of the nature of things, had their beginnings from the same authors. We are therefore inform’d that many of the professors of natural philosophy were well skilled in physick, and that the most illustriousof these werePythagoras,Empedocles, andDemocritus.Hippocrateswas the first who separated these studies; but he did not separate them in such a manner as to pull them asunder entirely, but so as to split that comprehensive science into several more minute members, that many might cultivate divided, what one could not learn entire; but that neither should desert what nature made inseparable.

That part of this science, which considers body merely as body, has retain’d the name of natural philosophy: others went by various names, according to the different sorts of bodies of which they treated. The human body is the object of physick, which without natural philosophy islame; for he is but a dunce in the art of healing, who is not acquainted with the forces of bodies, and the laws of motion: nor do professors of physick care to undertake the education of those, who are ignorant of natural philosophy. But if physick is greatly indebted to this science, it can in some respects return the favour, and physicians have return’d it in many instances: forGilbert, who first satisfactorily explain’d the phænomena of electricity, was a physician, as was likewiseBoyle, who promoted natural knowledge more than any other philosopher; andBoerhaave, whose experiments upon the elements have given a new face to this science; and to pass over many others in silence, the illustriousMuschembroek, whois universally allow’d to surpass all others in this article.

And there is some connexion, though perhaps not so close, between your studies and physick, illustrious professors of history and languages; for what physician would not be asham’d to be ignorant of history and the humanities? Who would not be desirous of consulting the Arabian physicians in the originals, as none of them has hitherto been faithfully translated? Are there not likewise certain parts of history, which physick alone can throw proper lights upon? Is notCelsusa physician, whose works all that are desirous of speaking Latin in perfection, study night and day?Pliny, in whom we meet not merely with helps for acquiring the Latin language, but withthe purest Latinity, though he did not practise physic, understood it perfectly, and is entirely taken up in explaining it.Areteus, whom we respect as a master of the healing art, is conspicuous for the elegance of his Greek.Galenhas an eloquence peculiar to himself. So hasAlexander. And those who cultivate the Arabic language, boast that it is no where to be found in greater purity than in the writings of physicians.

It appear’d to me at first sight, that on so copious a subject it would be easy to make an oration; but upon maturer deliberation I began to think quite otherwise; and so, having laid down a burthen too heavy for my shoulders, and left it to more sublime geniuses, I kept to my practice,my labour ishere engaged, and not my eloquence; and, having resigned the hopes of declaiming like an able orator, or soothing your ears with the allurement of words, I have chosen this subject, as capable of pleasing you by its own force; and as it is sufficient barely to lay it before you, it requires no ornaments:

De tauris dicit arator, navita de ventis.Quod medicorum est promittunt medici.The plowman talks of oxen, the sailor of the wind.Physicians offer what belongs to their profession.

De tauris dicit arator, navita de ventis.Quod medicorum est promittunt medici.

De tauris dicit arator, navita de ventis.

Quod medicorum est promittunt medici.

The plowman talks of oxen, the sailor of the wind.Physicians offer what belongs to their profession.

The plowman talks of oxen, the sailor of the wind.

Physicians offer what belongs to their profession.

And addressing myself to learned men as a physician, I shall treat of the healthof studious men; and here again I must request your indulgence:

Dira per incautum serpunt contagia vulgus.A dire contagion through the vulgar spreads.

Dira per incautum serpunt contagia vulgus.

A dire contagion through the vulgar spreads.

But whilst I was hurried about to attend a crowd of patients, I had no leisure to polish my work; therefore I have without method thrown together my thoughts and observations on this useful topic.

It is an old complaint, that study, though essentially necessary to the mind, is hurtful to the body; andCelsushas intimated the necessity of a remedy. Those that are of weak constitutions, says he, as most studious men are, should take greater care thanothers, that what is impaired by application to their studies may be repair’d by attention to their constitutions. AndPlutarch, an admirable judge of what is right and becoming, declares it to be a shame, that the learned should spend days and nights in useless investigations, and at the same time neglect the art of preserving their health; being, doubtless, ignorant that the healing science was formerly look’d upon as a part of wisdom, and that those chiefly requir’d medical assistance, who have impair’d their bodily strength by anxious thought and watchfulness.

There are two principal sources, from whence all the sufferings of the studious flow; the constant exercise and application of the mind, and the continual rest of the body; for they areas indolent in body, as they are busy and active in mind. By enumerating the ills, that arise from both causes, a dreadful crop of diseases will be display’d.

Let metaphysicians bewilder themselves in inquiries, how the mind governs the body, and is govern’d by the latter in its turn; physicians, descending to considerations of less importance, but of greater certainty, perhaps, and little sollicitous about the causes of this mutual government, and but confining their inquiries to phænomena, know by experience, that certain emotions of the mind necessarily arise from certain conditions of the body, and that by particular emotions in the mind particular changes are unavoidably produc’d in the body, andthat whilst the mind thinks, some part of the brain is stretch’d. We make no other inquiry; it would be of no use to know any thing farther.

So close is the connexion between mind and body, that we cannot well conceive the operations of the one independent of some correspondence with the other. For as the senses are incapable of conveying the materials of thought to the soul, without the motion both of their own fibres and those of the brain, so, whilst the mind revolves these cogitations, the organs of the brain are more or less stimulated to act, stretch’d, and have oscillatory motions excited in them. The mind agitates the machine; and these are the labours of the medullary part, which, being so tender, does not suffer theless by these motions; and every man easily feels that in himself, which the strongest arms experience after the most violent exercise.

For which of you, that has been addicted to a studious life, has not often found, after intense thought, that the innermost part of the brain has been affected by a troublesome heat, and intense pain, such as the muscles feel when fatigu’d with long labour? Nor does the medullary part of the brain suffer alone, but the very eyes themselves can perceive the force of the thinking soul, extended beyond the brain: for whilst we look upon a man that meditates seriously, all the muscles of his face appear stretched, nay sometimes convuls’d. Nor does the brain, the medulla of which is the source ofthe nerves, suffer alone, but they themselves are hurt; andPlatohas admirably shewn, in the masculine style in which he so greatly excell’d, how much the exercise of the mind prejudices the body. “Quando anima, inquit, corpore admodum potentior est, exultatque in eo atque effertur, totum ipsum intrinsecus quatiens languoribus implet. Quando etiam ad dicendum, investigandumque, collectis in unum viribus, vehementer incumbit, liquefacit prorsus corpus, & labefactat; denique cum ad dicendum, differendumque privatim & publice ambitiosa quadam concertatione contendit, inflammat corpus atque resolvit. Tam arcta enim lege consortii, sicRamazzini, fœderantur anima & corpus ut omnia tam bona quam mala unius in alterumvicissim corrivent, ac veluti, ex corporis nimia exercitatione, anima ad mentis functiones languescit, ac torpet, sic ob nimiam animæ contentionem, circa sapientiæ studium, corpus marcescat necesse est, absumptis nempe spiritibus, communi scilicet instrumento ad materiales & spirituales operationes rite obeundas.” “As the mind, says he, is far more powerful than the body, and exults and is elate therein, it affects it inwardly, and fills it entirely with languor; and when, by gathering together its strength, it applies earnestly to learning and to the investigating of things, it quite dissolves and unhinges the body: finally, when with an ambitious emulation it exerts itself to speak and harangue both in private andpublic, it inflames the body and relaxes it. For, asRamazziniobserves, the soul and body are united by so firm a league, that all the advantages and disadvantages of the one must affect the other; and as the soul is rendered languid in the mental functions, and become stupified in the same manner by the too great application of the mind to the study of wisdom, the body must unavoidably pine away, the animal spirits being consum’d, which are the only instruments of rightly performing both material and spiritual operations[2].” These are indeed observations highly just. For he who is not ignorant what a multitude of nerves there are in the animal system, who is sensible that there is no functionthat can be performed without them, will easily apprehend that by the fatigue of the medulla a languor may be brought upon all the nerves, so that the several functions may be weakened, and the strength of the body may, without its being exercised, be totally exhausted.

It is universally known that there are books compos’d without any strength of genius, which appear quite insipid and unaffecting to the reader, and only tire the eyes; but those that are compos’d with an exquisite force of ideas, and with an exact connexion of thought, elevate the soul, and fatigue it with the very pleasure, which, the more compleat, lasting, and frequent it is, breaks the man the more[3].

Malebranchewas seized with dreadful palpitations in readingDescartes’sMan; and there is still living at Paris a professor of rhetoric, who fainted away whilst he was perusing some of the sublime passages ofHomer[4].

The head itself, and the nerves, and the stomach which is fuller of nerves than any other part, first suffer for the errors of the mind.

An eminent person, who had impair’d his health by too intense anapplication to study, was immediately seiz’d by a terrible vertigo, if he happen’d to listen attentively to a person telling a story. He likewise complained, that nothing could give him greater uneasiness than his attempting to recall the memory of any thing, for then he was put to the greatest pain imaginable, and sometimes seiz’d with a fainting fit, attended with a sense of extreme lassitude. Nor could he desist from his effort after he had once begun it, though he labour’d ever so much for that purpose; but was under a necessity of proceeding as he had begun, till he fainted away[5]. The illustriousViridet, formerly my fellow-citizen, knew a woman who, whenever she us’d any application of mind,was seiz’d with a severe fit of the colic[6]. And a late author speaks of a man who never either thought intensely, or experienc’d any lively sensation, or was put in a passion, but his whole arm immediately swell’d up[7]. Both of which cases may be explained by the defect of the nerves alone, and the action of the mind upon the nerves.

Daily observation proves the force of the mind’s action upon the stomach; and this every man has an opportunity of experiencing in himself; for the more intensely any man thinks, and the more strongly he exerts the reflecting powers of his mind, the more slowly and with the greater difficulty,cæteris paribus, does he digest what he eats; and, on the other hand, the freer a man’s mind is from reflexion, the more readily and the better he digests. It is observable that fools always eat and drink a great deal, and yet digest perfectly well, even though they lead a sedentary life, and do not surpass others either in the bulk or strength of their bodies: whilst men of genius and abilities, though they have strong muscles, and take exercise sufficient, are obnoxious to crudities in the stomach and slowness of concoction[8].Boerhaave, who resided a long time in a city renown’d for learning, has observ’d that studies excite a disagreeable sensation at the upper orifice of the stomach; and that, if this be neglected by the studious,madness ensues[9]. My illustrious friendPomeknew a man of learning, who had made his stomach so infirm by intense application, that immediately after eating he vomited[10]. I myself have seen some, who, when their minds were wearied out with constant study, being taken ill, at first lost all appetite, then were seiz’d with a weakness of their whole bodies, and at last with dreadful paroxysms, which began with vomiting, and ended in convulsions and a total privation of their senses.

Soon, by an unavoidable fatality, the disorder that had affected the body recoils upon the mind; for the Author of nature has ordain’d that most of theoperations of the latter should stand in need of the assistance of the former; which has given occasion to the following just observation ofPlinythe younger[11], and long before him it was observed byDemocritus, that the mind is supported by what supports the body. “Augescit mens cum adest sanitas, adeoque huic ut prospiciant, qui recte sentiant consentaneum est: ubi vero corporis habitus dolet nec mens ad virtutis meditationem est alacris.” “The mind acquires new vigour whilst the body is in health; therefore all those who think justly will take care of the latter: but, when the body is in a painful state, the mind is less alert in the meditation of virtue[12].” Should it thenseem surprising, if, when the tenor of the brain and nerves is broken by the efforts of the mind, the latter should decline in its turn? First of all it is depriv’d of its fortitude; distrust, terror, and melancholy, seize upon it; and he who would have stood undaunted amidst a falling world a few months before, is every moment fill’d with terror and consternation, as soon as his nerves are affected by a hypochondriac disorder. Relentless tyrants may have condemn’d to death philosophers whom they hated; but it never was in their power to subject them to the dread of death, which they had long shaken off. O how much more cruel would they have been, if they had granted them their lives, and had it in their power to torment their minds with hypochondriacal terrors!

Thus render’d unequal to the task of study, the learned are at last under a necessity of quitting their belov’d pursuits; for, as the strength of their nerves diminishes, their attention fails, the memory begins to lose its tenaciousness, the ideas are obscur’d, and an uneasy sensation of heat over the whole head, a dreadful palpitation, the most extraordinary weakness, and a groundless fear of approaching death, oblige them to discontinue their application. Their strength being at last repair’d by rest, nourishing aliments, and exercise, they renew their assiduity in study, but are soon oblig’d to quit their books as before. Thus the whole day is lost; and when evening approaches and they retire to bed, their weakness and anxiety make them pass their nights most dismally, whilst the great mobility of their nerves preventstheir sleeping, and sometimes increases to such a degree as totally to deprive them of the power of thinking. I know a young man, upon whom an intense application to study had this extraordinary effect, that, if he read even a few pages, he was torn with convulsions of the muscles of the head and face, which assum’d the appearance of ropes stretch’d very tight.

Nor does too intense an application produce only slight and transient convulsions of the muscles; it likewise renews and generates the most dreadful nervous disorders.Galen[13]mentions a grammarian, who was seized with a fit of the epilepsy, whenever he meditated profoundly, or taughtwith vehemence. I myself have seen instances of it. And the illustriousVan Swietenlaments the case of youths of the brightest hopes, who have been seiz’d with a dreadful and incurable epilepsy, upon being compell’d by severe masters to apply to their studies with scarce any intervals of relaxation.Hoffman[14]makes mention of a young man, who, as often as he weary’d out his memory and his genius by attentive study, was seiz’d with a momentary epilepsy, a palpitation of the heart, and a trance; but when he remitted of his assiduity, was always tolerably well. This the celebratedPetrarchlikewise unhappily experienc’d, being seiz’d with an epilepsy through his great application to study, to which he was immoderately attach’d. In a public promotion, oneof the candidates for literary honour, after having pursu’d his studies with the moil arduous application both day and night, through a too great attention to his oration, that he might be able to say it accurately by heart, was suddenly seiz’d with a catalepsy and fell down[15].

The labour of the mind not only produces nervous disorders, but, by means of the nerves, gives rise to other complaints. An eminent mathematician, who was troubled with an hereditary gout, and had always liv’d soberly and chastely, hasten’d a paroxysm by applying a long time to the solution of a difficult problem[16]. And the case of the chevalierde Pernayis very extraordinary. After four months of the closest study imaginable, and without any previous disorder, his beard fell first, then his eye-lashes, then his eye-brows, then the hair of his head, and finally all the hairs of his body[17]. Did this proceed from the great relaxation of the roots, from which the hairs grow; or from the want of nutrition? Certain it is, that an intense application of mind relaxes the whole corporeal frame, and prevents all nutrition for two reasons; for this is the effect of thought, not upon all, but upon most constitutions, that it accelerates the pulse, and produces a fever, which, by dissolving the nourishing jelly of the fluids, occasions paleness, leanness, consumption, and a sort of wasting of the nerves; on theother hand, the cessation of the action of the nerves, is capable of producing it. Nor does it less cease in the whole body, whilst it is obstructed by application of mind, than when it is stopped by a swelling or a ligature in any part. We should not be too inquisitive in prying into causes; and many circumstances relating to nervous disorders will for ever remain unknown: but if any one should be curious to know how the too great tension of the nerves is hurtful, I will briefly give him my sense of the matter. The body is exhausted by too great an evacuation; hence arises weakness, an extraordinary tenuity of the humours, and, what it is generally productive of, a diseased mobility. Suppose the blood were to run copiously from a wound, or the gastric fluidswere to be pour’d forth by the anus, or the breasts suck’d too long, or a greater discharge of saliva made by spitting, or the wretched body were to be troubled with a long diabetes, or in short, any other evacuations were too much increased, the strength would decline, and the health be lost; but whilst the nerves act, their fluid runs out of the body, and carries off the strength with it; nor is there any thing in the body either more labour’d, more necessary in many animal functions, or more intimately connected with strength. In studious men, therefore, a perpetual dissipation of the nervous fluid springs from the incessant action of the nerves, attended with weakness, and an extraordinary mobility, from whence all the above-mention’d diseases easily take rise; theseare very dreadful, but diseases still more dreadful remain to be describ’d.

It is not easy for the mind not to throw out at will such motions as it has powerfully conceiv’d; and this is a second cause of the diseases of studious men, from whence spring so many errors and wanderings of the mind, to be chang’d for death only, so many phrenzies and deliriums: for whilst ideas no longer answer to their external objects, but to the internal disposition of the brain, the latter being agitated by its own motion, either entirely, or in part, is unable to receive new vibrations, to be transmitted, all, or some, by the senses; whereas those that are spontaneous cannot be check’d.

The brain ofBlaise Paschalwas so vitiated by passing his life in the laborious exercises of study, thought, and imagination, that certain fibres, agitated by incessant motion, made him perpetually feel a sensation, which seem’d to be excited by a globe of fire being plac’d on one side of him; and his reason being overpower’d by the disorder of his nerves, he could scarce banish the idea of the fiery globe being actually present.Spinellopainted the devils thrown from Heaven by the Almighty, and gave so fierce a countenance to Lucifer, that he was struck with horror himself; and during the remainder of his life, his imagination was continually haunted with the figure of that demon, upbraiding him with having made so shocking a portrait of him. There aremany others, whom the force of genius too much rous’d, has for ever hurried beyond the boundaries of truth.Gaspar Barlæus, who was at once an orator, a poet, and a physician, was not ignorant of this danger, concerning which he admonish’d his friendConstantius Huygens[18]; but being blind with regard to himself, he by immoderate studies so broke the force of his sensorium, that he thought his body was made of butter, and carefully shun’d the fire, lest it should melt him, till being at last tir’d of his excruciating fears, he leapt into a well.I must still grieve for a friend of a penetrating genius, an excellent understanding, of strict morals, and one that seem’d born for a better fate; who being animated with too great a love of learning, and in particular of the medical science, by reading night and day, observing, making experiments, and meditating, at first became sleepless; then began to talk, sometimes incoherently, and sometimes rationally; at last run mad, and having scarcely escap’d with life, never recover’d his reason. I have known many others, who by study alone were first rendered phrantic, or crazy, and at length became idiots. I love, esteem, and honour an illustrious man, and a man of extraordinary abilities, who being twelve hours intent upon settling a difficult memorial, after having finish’dhis work, became delirious till a soft sleep quieted the state of his nerves. Observers give us accounts of many similar cases, and I was inform’d by a witness who may be confided in, thatPeter Jurieuwas formerly famous for his talent at disputing, by his labours in writing books of controversy, and expounding the apocalypse, so disorder’d his brain, that though he thought like a man of sense in other respects, he was firmly persuaded that the seven fits of the cholic, with which he was tormented, had been occasion’d by a constant fight between seven horsemen that were shut up in his bowels. There have been many instances of persons, who thought themselves metamorphos’d into lanterns, and who complain’d of having lost their thighs.

But those are affected in the most dangerous manner, who dwell too long upon one and the same thought; for thus one part of the sensorium being longer stretch’d than the rest, without being ever reliev’d by the others in their turn, is the sooner broke; for as the body suffers more if one or but a few muscles alone act, so the brain is the less fatigued when various parts act successively; the part which discontinues recovers its strength, whilst the others are at work; and that is durable which does not want alternate rest.

Many years ago I knew a woman, who appear’d to have very good sense for five and twenty years; but having, unhappily for her, embrac’d the sect of the Herrenhutters, she became entirelyinflam’d by the love of our blessed Saviour, and of him alone; and she dwelling entirely upon this idea both day and night, it so broke the tone of her brain, that in a few months time she became an idiot; but still she was so mindful of her Lamb, that visiting her every day for half a year together, and frequently addressing my discourse to her, I could never hear any other words from her thanmy sweet Lamb; and this she utter’d every half hour, with downcast eyes, and was the only word she spoke for a year and a half; which time being elapsed, she pin’d away and died. And to pass by other examples, there was not long ago in this academy, a young man of bright hopes, who being too earnestly solicitous about squaring the circle, died mad in the Paris hospital.

The third cause of the disorders of the brain, is, that law to which the human machine is subjected; that a new quantity of blood should be added to the part that acts. The illustriousMorgagniknew a man of learning at Boulogne, who whenever he gave his mind to abstract meditations in the morning, before he rose, was sure to bleed at the nose for a short time after[19]. Therefore as often as the brain increases its action, it is moisten’d with an additional quantity of blood, which, giving a new tension and a quicker motion to the vessels, brings on both the sense of pain and heat already mentioned, and many more grievous symptoms; namely, according to the different state of the brain, of theblood, and external objects, it occasions dilatations of the veins and arteries, obstructions of the nerves, inflammations, suppurations, scirrhous tumours, ulcers, dropsies, and thence head-achs, deliriums, drowsiness, convulsions, lethargy, apoplexy, and continual obstinate watchings, which cruelly torment the studious, and afflict them with new diseases; for what diseases, what perturbations of the mind do not protracted watchings give rise to? The greatBoerhaavewas six weeks without sleep, after profound study and meditation; and at the same time so indifferent to every thing, that scarce any object whatever affected him[20]. And which of you, learned auditors, has not found by experience,that a slight and disturb’d sleep, a sleep that scarce gives refreshment, generally follows a day pass’d in study. A slight irritation of the brain causes want of sleep; from one more considerable arise convulsions and drowsiness; from the greatest of all a mortal apoplexy, which disorder often puts an end to the lives of learned men. The reason is, that that part suffers which was guilty of the excess, and whilst the strength of the brain is relax’d by study, and fresh blood is forc’d into it, it must sooner or later be quite overwhelm’d, especially at the time that some new cause adds force to the blood that impells it; thence it has frequently come to pass, that learned divines in preaching, and learned professors in delivering their lectures, or disputing, as was the case with the celebratedCurtiusat Leipsick, expir’d on their very chairs; andLivythe historian has preserv’d to us the history of kingAttalus, who died in the assembly at Thebes, whilst he was animating the Bœotians by an harangue to enter into an alliance with the Romans.

I saw a reverend pastor, who on Whitsun-sunday, after having preach’d long and with vehemence, whilst he was distributing the host to the people, was first seiz’d with trembling, then stammer’d, then was delirious, then fell down in an apoplectic fit, and continuing delirious ever after, though in an advanc’d age, liv’d for some months in a state of infancy. The celebratedMorgagnilikewise mentions a preaching monk, who was seiz’d with a violent apoplexy beforehis congregation, and quickly died; his vehemence of delivery conspiring with a plethora to destroy him[21]. A professor at Berne, deeply versed in the oriental languages, a man in the prime of life, but of indefatigable industry, not long since sunk into a second infancy, and a state of idiotism, his brain being overflow’d by water, which stagnated in it[22].

We must not forget, in enumerating the injuries suffered by the brain from this overflowing of the blood, that the disorder of the nerves which causes the hypochondriac disposition, is increased; their little tubes being dilatedare constantly weaken’d, grow soft, and make less resistance to impressions, which is one of the chief causes of the hypochondriac disorder.

Nor do the sufferings of studious men end here, since from another law, which holds equally in the animal œconomy, a fourth cause of the disorders of the learned springs from an over violent labour of the mind; for the animal fibre is indurated by being used, the whole machine grows callous as it grows old; the parts that are exercised by labour become hardened in workmen; the brain of studious men contracts a callosity, so that becoming unequal to the task of forming ideas, they fall into a premature dotage: thus the too great softness of an infant’s brain, and the too great hardnessof a brain occasioned by study, are equally ill adapted to produce those vibrations, without which the force of thought is lost. Let the fibre be moisten’d with water, or stiffened with lime and sand, it in both cases becomes equally incapable of performing its function. At first the memory is impair’d, asGalenjustly observes, and then reason itself is disturb’d[23].

Nor is there any necessity that the mind should meditate great and sublime objects, to impair the strength of the nervous system; a too protracted use of the eyes has often given rise to innumerable nervous disorders; concerning which, the testimony ofGunziusis of the utmostauthority[24]. And every weak man must know by experience, how much too great a use of the eyes weakens the head. Of this I have already given an example, and have often found it by experience; for when I contemplate any object a considerable time, after the fit of a fever, or any other disorder, and before my health is quite recovered, I am seiz’d with a vertigo, a sickness in the stomach, and a disagreeable listlessness of the whole body.

In order to vindicate literature from the charge brought against it, you will doubtless object, that many men of profound learning, have liv’d to the most advanc’d age, and retain’d their powers both of mind and body unimpair’dto the last. I have heard of many, I have myself seen more; nor can either you or I ever forget that truly illustrious man, that man of universal learning, who as he was worthy of it, enjoy’d general love and veneration; who was the ornament, honour, and delight of this academy for above fifty years, and whom we all with equal wonder and satisfaction saw enter upon his 90th year, without either his reason, or his senses being in the least impair’d. But all are not equally happy, and there are few men endued with such strength, both of mind and body, as to undergo such labours with impunity, if even those can be said to undergo them with impunity, who attain to that stage of life, which they perhaps would have greatly exceeded, had they liv’d in adifferent manner. Some men are by nature insatiable in drinking wine, others are born cormorants of books, and never glutted with the acquisition of learning: nor should it be pass’d over in silence, that almost all the learned men, who are look’d upon as its masters by the human species, all liv’d to a great age; asHomer,Democritus,Parmenides,Hippocrates,Plato,Plutarch, LordBacon,Galilæo,Harvey,Wallis,Boyle,Locke,Leibnitz,Newton,Boerhaave. Can it then justly be inferred, that violent exercises of the mind are not hurtful? Take care how you draw so false a conclusion? But, as I said awhile ago, some men are born with happy constitutions for meditation, and perhaps that excellent constitution of the fibres, productiveof longevity, is the same that produces great geniuses;

Mens sana in corpore sano,A sound mind in a healthy body;

Mens sana in corpore sano,

A sound mind in a healthy body;

and consequently the great men, whom I have just mention’d, owed their reputation more to their extraordinary genius, than to industry and application; and prevented the ill effects of their severer studies, by allowing themselves intervals of leisure, by taking proper exercise, and by the dissipation both of business and amusement. Nor did they lead the life of abstracted students, a species of men little known to the ancients, and who took their rise first at the declension of literature, were renew’d at its revival, and may be properly compar’d to the Indian fakirs;for both bid farewell to the human race, and both of their own accord, and generally without any emolument to society, emaciate and inflict austerities upon themselves; the former by the sun, by cold, by nails, by chains, by whips; the latter by books, manuscripts, coins, monuments, and almost all by inaction, and the want of bodily exercise. This is another, and a most prolific source of the disorders which afflict men addicted to study; for the human machine was form’d and intended for action by the supreme artificer: therefore health is inseparable from action, which will be easily conceiv’d by whoever examines the human body with attention.

It consists of containing and moving vessels, contained and moved fluids: ifthe fibres or vessels have a proper tone, if the fluids have a proper consistence, if the motions, by which they should be continually agitated, are neither too violent, nor deficient, we enjoy a good state of health. But it should be taken into consideration, that motion is here the chief agent, for, that alone being chang’d, the whole state of the solids and fluids is chang’d likewise: if it be increased, the solids grow harder, and the fluids are compress’d; if it be diminished, the fibre becomes relaxed, the density of the blood is lessened, for the whole body is form’d of a chyle, which is softer and lighter than any part of the body, either solid or fluid, whose small particles a continual motion unites and strongly compresses; and if this motion shouldfail, the parts must prove deficient in their due firmness.

But the heart is the source of all the motions in the animal machine, the principle which puts the whole mass of fluids in motion, but is not alone sufficient for that purpose; wherefore nature has given it many helps, which never discontinue or remit, but the circulation becomes slower, and diseases arise from the motion of the fluids being retarded. The chief of these helps is the muscular motion, whose extraordinary force in quickening the circulation, the most ignorant surgeon every day displays to the eyes of all spectators, by an easy experiment, when upon opening a vein he bids the patient move some cylindrical instrument round about in hishand, in order to accelerate the emission of the blood: nay, every man may easily perceive in himself, how much the quickness of the pulse is increased by the motion of the body; and these are the effects of motion, it sharpens the appetite, it strengthens the fibres, keeps up a due temperature of the fluids, promotes all the excretions, fortifies the mind, and gives a pleasing sensation to the whole nervous system; whereas by too great sloth, the muscular strength is first destroy’d for want of practice; and from a neglect of exercise there springs an impotence of motion: the circulation which is carried on only by the strength of the heart and the vessels, and destitute of external helps, first languishes in the most minute vessels, and then in every part of the body; the heat decreases,the humours stagnate, and contract a vitious disposition; for some of them lose part of their density, others part of their tenuity, and they all become glutinous, and of consequence unfit for secretions; therefore what should be secreted is retain’d, the body is loaded with a mass of adventitious humours, it is destroy’d by their acrimony, the vigour of life is benumb’d, the strength declines, the blood is dissolved to water; hence arises a dropsy, a disorder in a manner epidemical to men of learning, by which the brain is often affected. An instance of this I lately saw, with concern, in an eminent man, whose case I discover’d too late, and who not by literary pursuits, but other exercises of the mind, and total inactionof body, had broke a constitution which once was robust[25].

Those parts suffer the most, which having but weak solids, they want external helps more than any others; hence those organs are most affected by inaction,which, being contained in the abdomen, perform the first digestion of the aliments: the strength of the stomach is diminish’d, the nature of the gastric fluid is chang’d, the aliments make a longer stay in it, and, not being sufficiently subdu’d by the animal force, they go through their spontaneous changes which they would have undergone out of the body. Most vegetables retain their tartness, which, by vellicating the nerves, occasions pains and convulsions; acid eructations arise, the cardia suffers pain, the throat is parched, and the teeth blunted. On the contrary, both flesh and eggs rot, and fat aliments grow rank: hence proceed putrid eructations, immoderate thirst, and continual fluxes; digestion is always difficult, troublesome, and malignant; the aliments cease to affordnourishment, nor do they any longer repair, but irritate and weaken.

The exhaling vessels no longer pour forth a dewy, mild, and saponaceous lymph, but they throw out a thick glue, which affects the sick with a constant pain and sense of a heavy weight, and of cold at the stomach, and creates the utmost loathing. The consequence is the same when the intestines, being of the same structure with the stomach, suffer the same injuries: the action of respiration first begins to fail, whose alternate compressions, whilst it is accelerated by the muscular motion, compress and strain all the viscera of the abdomen; their irritability is lost, the body is generally costive; there is here likewise accumulated, a troublesome phlegm, theprolific mother of diseases. Thus it once happen’d to the celebratedJustus Lipsius, professor of history at Leyden, who being long ill, and under the care of his illustrious colleague and friendHeurnius, found no relief till he had voided a substance resembling the intestines both in figure and colour; it was a tough and viscid phlegm, gradually collected in the whole tube of the intestines, through a sedentary life wasted by study; and this phlegm, turning to putrefaction, made a jakes of the whole body. The fomes of the disease being thus purg’d off, he was restor’d to health[26].

The collected excrements compress with their bulk the neighbouring parts,irritate the intestines by their corruption, and by absorbing the putrid matter infect the whole mass of blood. From all these causes put together arise those excruciating pains in the bowels which often torment the studious, and are with difficulty cur’d, as they are perpetually renew’d by errors in diet[27]. Hence that troublesome flatulency, so hurtful to sedentary men, which torments the learned a thousand different ways, and often passes for other disorders.

The intestines are not only affected, but the functions of the neighbouringparts are disturb’d, as well from the violence of the compression as from their own diseases; the pancreatic juice grows vapid and stale, the functions of the spleen are vitiated, the repositories of the bile are much disturb’d; by its stagnation it loads the liver, forms obstructions in it, thickens and grows hard itself, and flows slowly to the intestines; whence their disorders, especially those of the jejunum, and vices of the chyle, increase; being scarce able to pass through the narrow neck of the cystic duct, it often concretes into a stone, and occasions those severe colics with which the celebratedIgnatius, founder of the Jesuits, was formerly afflicted, and with which the learned are often tormented[28]. If atlength by stagnating it putrifies, it then erodes, ulcerates, inflames, and assumes the appearance of all the innumerable disorders of the liver, and produces inconceivable anxieties. These are likewise caus’d, though with less danger, by that cruel disease call’d the hypochondriac; the first species of which, mention’d above, and call’d the nervous, is occasion’d by excessive labour of the mind; the other, I mean the abdominal species, arises from a disturb’d circulation in the abdomen. With both these disorders the learned are afflicted, and therefore seldom or never live free from this evil; and, whilst one of these adds force to another, they are seldom entirely cur’d of them[29].

Considering they occur so frequently, it is hardly necessary to give examples; but if I were to cite examples, the first that would occur to my mind would be that of the illustriousSwammerdam, that sagacious inquirer into nature, who was so full of atrabilary humours, that he scarce vouchsafed to answer those who spoke to him, but look’d upon them with an unalter’d countenance; and, when he took his seat as professor, sat with a face of astonishment, and made no answer to the objections of his opponents. Finally, having, before his death, wasted away with a phranticmelancholy, he burn’d all the manuscripts he had by him in a fit of madness: being reduced in appearance to a skeleton and the mere figure of a man[30], he died at length of a consumption.

It has indeed been observ’d, that this species of melancholy in some measure promotes learning, by increasing the penetration; for, whilst melancholy men are intent upon one idea only, the mind contemplates this object alone, and considers it on every side; nor is it distracted by other pursuits. But who ever proceeded to this pitch of madness, as to desire to purchase an increase of discernment at such a price? Of what advantage is sciencewithout health? He knows too much, who is render’d unhappy by his knowledge.

It cannot indeed be denied, that there are men whom nature has endow’d with a Milonian stomach, and intestines of iron, who can bear with impunity the labour of the mind, bodily inaction, and excesses of gluttony. But are they therefore more happy? By no means; for then the vessels are overwhelm’d by the load of humours, the cellular membrane swells with fat, the viscera are press’d on every side, the whole habit grows turgid, they become heavy and indolent, the slightest motion puts them quite out of breath, and they sweat all over; at last they die before their time, either of apoplexy, a suffocating catarrh, orother diseases occasion’d by plethora: and it has been justly observ’d, that too strong a stomach has often prov’d fatal to the learned[31].

There is no part of the body which is not at last affected by inaction; for the blood being vitiated, all the parts, which it washes, catch the infection sooner or later; the lungs are overwhelm’d with a mucous substance, this gives rise to a cough, a shortness of breath, an asthma, an imposthume. This the illustriousTriglandusunhappily experienc’d, who, having contracted a bad habit of body by a studious and sedentary life, from whichBoerhaavehimself dissuaded him, wasted away with an imposthume and died,after having suffer’d the most excruciating torments[32]. By the mucous matter being harden’d the lungs ofSwammerdamwere turn’d into a quarry, and he spit up small stones a long time before his death.

That the stone, and other severer disorders of the bladder, are the fruits of too assiduous an application to learning, is prov’d by the sad experience ofHeurnius,Casaubon,Beverovicius,Sydenham, and many others, amongst whom may be reckon’d the illustrious exile of Geneva, to whom Britain now boasts of having afforded an asylum[33].

Whilst all the excretions are disturb’d, the chief of them all, namely cuticular perspiration, is not free from disease. As perspiration is greatly promoted by muscular motion, which both prepares humours for secretion, and gives strength to the exhaling vessels; so is it greatly interrupted by the want of that motion; the humour that ought to be excreted is retain’d, and pollutes the whole mass of the fluids, and gives rise to rheumatic or catarrhous disorders and a troublesome phlegm. Of thisHoracecomplained long since, and with this complaint almost all men of learning are afflicted; for they can scarce read or write for any time, but they are immediately troubled with a slight running of the nose, or seiz’d with a cough.

From the same source are derived those irregular fevers, which often occur without any visible cause, whilst the unperspirable humours, which have been generated by the defect of the stomach, and the want of motion, are unable to pass the cutaneous vessels.

Perpetual rest is alone able to torture those nerves, which have been weakened by the labours of the mind; and it often quite destroys them, even in those who equally give themselves up to indolence both mental and corporeal. For the nervous system is the last work of the human machine, and if any function fails, the nerves are immediately affected; so that often from their defect, whenever it appears, there results a well-grounded suspicion of a disease in the stomach, or in someother part. They are therefore vitiated in the learned for two reasons; for, being plac’d between the mind and body, they are punish’d though innocent, let which of the two be in fault; nor do they however go unrevenged; for the injuries they suffer on one part they carry over to t’other, and thus, by a vicious circle, the mind hurts the body, and the body impairs the mind, and they with one accord injure and weaken the nerves.

The seminal fluid, which has been thought by some great men not to be very different from the nervous liquor, is likewise depriv’d of its force; and upon this principle, and from an accurate consideration of what each part in a father contributes to the formation of a son, it perhaps is not badly accountedfor, why strong and illustrious sons are seldom the offspring of illustrious men: for thepunctum saliensis contaminated at the first moment of life, whence it receives an injury which is not afterwards to be repair’d by any art; and whilst the mind of the father was entirely given up to meditation, and his corporeal functions totally neglected, the vivifying liquor was perhaps defrauded of that part of elaboration which it should have had from the brain, so as to give a proper tone to the brain of the embryo.

From that general laxity of the fibres, which is demonstrated to the senses themselves by the softness of the muscles, by the force of the artery, and by that laxity of the gums which throws out sound teeth without anypain; from that general laxity, I say, arises that weakness which oppresses so many learned men, and which I lately lamented to see, whilst, as a friend and physician, I sat by our belovedAlphonsus[34], to whom the wishes of the public had promis’d the age ofNestor; and all the hopes I had of his recovering his health were immediately banish’d, by a weakness greater than any I remember ever to have seen, and which the Herculean labours of his mind had brought upon a thin body. How great and irrepairable a loss was then sustain’d by religion, virtue, the church, the city, his unfortunate family, and the youth of this academy! What a man, what a colleague, what a friend have we lost,illustrious professors! one who, asEuphratesof old, was remarkable for the greatest sanctity of manners, for the utmost care in the discharge of all the duties incumbent upon him, which were many in number; one whose complaisance was equal, who was entirely free from austerity, whose presence excited reverence, and not dread, for he was severe upon vices, not upon men; whose learning was extensive, whose discourse was copious, various, and, above all, pleasing, and yet not without a Platonic sublimity; one, in short, who was capable of persuading and working upon such as were most averse to his documents: having liv’d in the utmost veneration, he left behind him the highest regret for his loss. But to return to our subject from this sad digression.

Thus have I treated of the two first causes of the diseases of the learned; others remain still to be spoken of; and the first that occurs, whilst I am upon the subject of inaction, is the very posture of constant sitting, with the body stooping, and the legs bent; for this both hurts the lower extremities, and, by obstructing the viscera of the abdomen, soon occasions all sorts of disorders arising from indigestion: and those learned doctors prudently consult their health, who indulge their meditations, not indeed standing, for that posture is not without its inconveniences, but walking. And this is one of the bad effects of sitting, that it greatly obstructs the passage of the blood in the abdominal veins, which makes it stagnate at the anus, where it meets with less resistance, andcauses those shocking piles that torment so many literati, and, though praised by some, certainly do much more harm than good.

Nocturnal lucubrations, which are hurtful upon many accounts, must have their place amongst the causes of disorders; for whilst a great part of the night is spent in study, sufficient time is not allow’d for sleep; nor does a gentle slumber succeed meditation; a circumstance which I have already lamented: for the oscillations of the fibres of the brain still continue, and that full ease of the internal senses is wanting which alone is capable of repairing our lost strength. They likewise pitch upon an unreasonable time for sleep; for nature has assigned the first approach of night as the propertime for beginning to repose; the night invites to sleep as well as the unwholesome air, and to this end its darkness and silence contribute: besides, the nocturnal air is cold and moist, and, when the sun retires, most animals feel their strength diminish’d, and night forces some of them to sleep even against their inclinations, as it does many plants.

The night air is so unfavourable to study, that the celebratedVan Swietenknew a gouty man, in whom the slightest application of mind, and even the reading of a letter, after sun-set, occasion’d a fit of the gout. Nor should we forget that study forces the blood into the brain, and that nothing can be more dangerous than to study in bed; forboth sleep, and the posture of the body in sleep, increases the quantity of blood in the skull.

Therefore nocturnal studies produce all those disorders which the want of rest gives rise to; the organs of sense are principally affected; their strength is exhausted, the fibres are either worn or agitated by violent motions; hence arise an incoherent series of thoughts, a luxuriant imagination, deliriums, dreadful head-achs, and, finally, a total privation of sleep, scarce to be cur’d by remedies, and which often occasions fatal disorders.

The injuries of watching are increased by the ill effects of candles, which infect the air by their gross vapour, so pernicious to the lungs, theeyes, and the nerves. It is, therefore, the highest advantage imaginable to go to bed betimes, and rise early in the morning.Aurora musis amica: Aurora favours the muses.

The close air, which they always use, is hurtful; but I shall speak of the air hereafter. Nor should their dirtiness be forgotten, as some learned men, entirely neglecting the care of their bodies, and not at all sollicitous about cleanliness, disgust others, and bring upon themselves those disorders which proceed from obstructed perspiration: for how can that skin perspire, whose pores are stopped up with dirt. Most of them are extremely faulty with respect to their teeth, which, being filled with putrid filth, and exhaling a most nauseous stench, firstinfect all the adjacent parts, and the very saliva of the sick person; soon after cause violent pains, and at last, falling before the time, leave the stomach destitute of the powerful aid of mastication.

Akin to dirtiness is the pernicious custom of some, who, deaf to the calls of nature, defer going to stool, and suppress their urine a long time, to avoid interrupting their studies; not reflecting that many dreadful disorders spring from this source.

For by too long a delay the secreted humours become too putrid, are attenuated, irritate the intestines or the bladder, vitiate the mucous matter, and sometimes occasion grievous disorders of the particular organ; theputrid matter being absorb’d by the vessels with which all the cavities of the body abound, pollutes the blood; and, which is still worse, the nerves become disused to obey the stimulus; nay, they sometimes, by too much tension, begin to grow paralytic; so that the expulsive force, for the voiding of excrements or urine, almost entirely ceases, and should every day be renew’d by art. Whilst the illustriousTycho Brahe, riding in the same chariot with the emperor, suppress’d his urine, he pay’d for his ill-tim’d modesty by death; and I even now have under my care a man of learning, who by a long suppression of his urine became unable to contain it; nor can he void it when he thinks proper, but it runs from him night and day by drops.

Retirement from all human society is likewise hurtful to them; for man, whom nature made for man, she intended also should be benefited by society.

But nothing renders study and application more pernicious than the sadness that accompanies them: study is capable of clouding the temper of the happiest man with melancholy: if real and external causes of grief are added to this, the mind, overwhelm’d with so many strokes, at last sinks under them, and in its own ruin involves that of the body. Anxious cares are likewise hurtful; so that I can hardly conceive how great men, whom the difficulty of their undertakings kept in unremitting meditation, and whom the uncertainty of events fill’d with continual anxiety, could go throughwith such great undertakings. Nature endow’dCæsar,Mahomet,Cromwell,Paoli, and some few more, with faculties which she refused other mortals, and which, notwithstanding, would scarce have enabled them to perform such great exploits without the assistance of sobriety and incessant action.

We should not, however, imagine, that the learned alone destroy their health by mental labour; it is of no consequence what the object is that engages the mind, if it applies a considerable time and with earnestness, it wastes both its own strength and that of the body. Kings, senators, ministers, ambassadors, and all those concern’d in the administration of public affairs, are subject to the same unhappy fate whichthe learned deplore, if they labour with equal assiduity in transacting public affairs, as the learned in perusing books. But it is their happiness, that, in the various business and dissipation of their places, they are oblig’d often to quit their closets, and even against their wills are, by a salutary necessity, compell’d to take frequent exercise: the chief use of this is, that it admirably prepares the blood for the generation of fresh animal spirits, and in the same time it brings a greater quantity of blood to the secerning organs, and so restores what thought had exhausted, and frames new instruments for the thinking mind. But nothing can force the studious from their books, and they are quite enervated by inaction: to palliate whichyou will perhaps bring some examples of men who have liv’d to a great age, though they used but little or no action. There are but few men; but you will, I doubt not, bring many women. Take notice, however, that, though they had not much muscular motion, they had many other helps, by which nature promotes the circulation of the blood,viz.an agreeable stirring of the passions, which excites, and does not destroy; a constant chearfulness and eternal loquacity, and other assistances of a similar nature: they likewise use but little food. The case is quite different with the learned: they do not live with the same sobriety; and therefore it is no wonder that they enjoy their health worse than any other class of men.

Thus have I laid before you the chief causes, from which the diseases incident to the studious take rise; and I should never make an end, were I to enumerate the inferior causes, which professors have a bad custom of assigning from their own invention: I shall therefore pass by all the secondary causes. But there are men, truly learned, illustrious votaries of the muses, who, besides the disorders that spring from too assiduous an application of mind, experience others, owing to the nature of the object that engages them. Anatomists often contract malignant fevers by breathing putrid air, and other diseases from the corruption of the bile, from the matter in which their hands are constantly immersed, a slight excoriation arising, or an inconsiderable wound, which sometimesend in their deaths. Chemical experiments are attended with danger, and an acid smoke, of a very penetrating nature, would have kill’d the greatBoerhaave, if there had not been at hand an alcaline spirit, which overcame the acid and expanded the compressed lungs. Botanists have been often hurt by the plants for which they have so strong a passion. These, and the like, rather relate to the disorders of artificers, (excuse the expression); but this discourse turns upon the disorders which study brings upon some of the organs.

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